The present invention relates to a method for reducing both the erosion and muzzle flash of gun barrels.
The trend of military requirement is toward ever-increasing muzzle velocities and ranges of projectiles. These increased requirements call for more energetic propellants, which in turn cause increased erosion of gun tubes due primarily to the hot gases generated when the propellants are fired.
Various techniques have been employed for reducing erosion of gun barrels. One method comprises plating, coating or lining the bore of the gun tube with a material more resistant to erosion than the gun steel, but this method has not been completely satisfactory.
The most satisfactory methods of reducing gun barrel wear include the addition of "wear additives" to the propelling charge, such as sheaths of polyurethane foam or super-slurper (a water gelled starch acrylonitrile copolymer) around the propellant, silicones such as dimethylsilicone, and mixtures of paraffin wax and titanium dioxide and/or talc. These additives have not been completely satisfactory, since they create other problems, such as residue formation with unpredictable effects on ballistics, smoke and midbore barrel wear.
The reduction of muzzle flash has been accomplished by use of the following principal methods: (a) addition of inorganic flash suppressants, e.g. potassium sulfate and potassium nitrate; (b) formulation of the propellant by including the inorganic flash suppressant as part of the propellant composition; (c) formulation of propellant having low isochoric flame temperatures; and (d) addition of a mechanical device to the muzzle. The addition of a mechanical device to the muzzle is cumbersome and hence impractical, while the use of low flame temperature propellants is precluded for future artillery systems in view of the requirement for higher muzzle velocities and greater ranges. Consequently, the two methods for flash reduction which have been predominantly employed are the addition of chemical flash suppressants separately to the propellant, and propellant formulations containing the flash suppressants. Of these methods the former is preferred, since it permits optimum location of the suppressant for each propellant charge and can be used with stockpiled charges, whereas the latter method does not permit optimization of suppressant location and cannot be used with stockpiled charges.
Current propellants frequently utilize an inorganic flash suppressant along with a wear reducer, such as a mixture of wax and talc and/or titanium dioxide. Flash suppressants presently employed with nitrocellulose based "smokeless powder", namely, potassium sulfate and potassium nitrate, produce smoke. Ideally, the flash suppressant should not contribute any smoke to the system.